Nepheline
is one of
the members of the Feldspathoidgroup of minerals that includes Cancrinite,
Haüyne,
Lazurite, Leucite,
Nepheline and Sodalite. Minerals with chemistries that are close to
those of the alkalai Feldspars, but are poor in silica
(SiO2)
content, are called Feldspathoids. Nepheline
is an extremely rare gem because clean, facetable crystals
are very rare and usually very small. Occassionally,
opaque cabochons can be found in colors of red, green,
brown or gray, some with minute inclusions that cause
a catseye effect. Colored varieties of Nepheline are
called Elaeolite. Elaelite is named from the Latin word
for oil because of its greasy luster. The main
source of facet grade crystals is Davis Hill, Mont Saint-Hilaire,
Bancroft, Quebec, Canada.